Existence map in C++

D:Temp>type vectorbool.cpp
#include <iostream>
#include <vector>

using namespace std;

int main() {
        vector<bool> vb(10);
        vb[5] = true;

        for (vector<bool>::const_iterator ci = vb.begin(); ci != vb.end(); ++ci) {
                cout << *ci << endl;
        }
}

D:Temp>cl /nologo /W4 /EHsc vectorbool.cpp
vectorbool.cpp

D:Temp>vectorbool.exe
0
0
0
0
0
1
0
0
0
0

if (mapObj.count(item) != 0)
{
   // item exists
}